While using Remote Desktop Manager from Devolutions company we've encountered a small issue. While using their great Remote Desktop Agent feature without using installer to do our job we were greeted with message that mfc120u.dll is missing and that SSH feature won't work.
Since this issue is very common for freshly installed Windows machines (both desktop and servers) starting at Windows 7 or even earlier version of Windows and ending up on Windows 10 and its server equivalent Windows 2012 R2. It's not just related to RDM software but any software that uses C++ code to run the app.
The Visual C++ Redistributable Packages install run-time components that are required to run applications that are developed by using Visual Studio 2008/2010/2013/2015, on computers that don't have Visual Studio installed. These packages install run-time components of these libraries: C Runtime (CRT), Standard C++, ATL, MFC, C++ AMP, and OpenMP.
To solve issue of missing mfc120ud.dll we just need to install Visual C++ Redistributable Packages. Normally it's done by installers but there are moments where either we're not using installer at all and simply want to run app in portable version or developer didn't provide installation package. Depending on program it can vary which version is required, and since it doesn't break anything you're perfectly fine to install all of them:
Microsoft Visual C++ 2008 Redistributable Package (x86 – 32 bit)
Microsoft Visual C++ 2008 Redistributable Package (x64 – 64 bit system only)
Microsoft Visual C++ 2010 Redistributable Package (x86 – 32 bit systems only)
Microsoft Visual C++ 2010 SP1 Redistributable Package (x64 – 64 bit systems only)
Visual C++ Redistributable Packages for Visual Studio 2013 (x86/x64 – 32/64 bit systems)
Visual C++ Redistributable Packages for Visual Studio 2015 (x86 and x64 – 32/64 bit systems)
The newer the app, the newer the system most likely it's enough to install newest possible version to solve missing mfc120ud.dll file problem. Make sure to reboot your system after installation if it doesn't work straight away.